A schematic configuration of a prior art projector system (see, for example, JP-A No. 2002-196740) is shown in FIG. 31.
In the projector system shown in FIG. 31, a projector unit 104 is provided with a projection lens 102. A screen 101 is arranged opposite to the projection lens 102. A laser pointer 103 is arranged such as to project light toward the screen when switched ON.
When using such a projector system, a presenter operates the projector unit 104 and thereby displays a desired image onto the screen 101 through the projection lens 102. Then, switching ON the laser pointer 103 directed toward a desired part on the screen 101, the presenter gives a presentation by pointing with the laser light to the part where the presenter desires to specify. Further, after the presentation has been given thoroughly by the presenter, or alternatively during the presentation, when a question is addressed from the audience, the presenter operates the projector unit 104 and thereby displays an image relevant to the contents of the question onto the screen 101.
Then, when a question is addressed from the audience concerning a specific part of the displayed image, the presenter moves the laser pointer 103 and thereby points the part where the questioner specifies on the screen 101.
When a plurality of persons address a question, each of a plurality of the questioners and the presenter possess a laser pointer 103 and thereby point the image on the screen 101 in some cases.
However, according to such a projector system, the presenter moves the laser pointer 103 with receiving an instruction from the questioner. Thus, it could take a long time before the optical image of the laser pointer 103 reaches the part where the questioner intends. As such, this system has been user-unfriendly. Further, in a possible situation that the image need be changed in response to an instruction of the questioner, the presenter need change the image into a desired one on the basis of oral explanation of the questioner. This approach has a poor operability, and takes a long time before a desired image is displayed.
Furthermore, when a part of the image projected on the screen 101 has been expanded, the presenter specifies a part to be expanded, on the basis of oral explanation of the questioner. Then, the presenter operates the projector unit 104 and thereby expands on the screen 101 the part of the image where the questioner intends. Such a process is unavoidable and hence causes much time and effort.
Further, it has sometimes occurred that when the presenter and a plurality of questioners point the image on the screen 101 simultaneously with the laser pointers 103, the pointing operations with the laser pointers 103 are mixed up and hence cause confusion in the display on the screen 101.